1. Field of Invention
The present invention relates to generators of static or direct current magnetic fields, especially those for therapeutic applications.
2. Description of the Prior Art
There has recently been an increased interest in therapeutic application of magnetic fields. There have also been earlier efforts of others in this area. The recent efforts, as well as those earlier made, can be categorized into three general types, based on the mechanism for generating and applying the magnetic field.
The first type were what could be generally referred to as systemic applications. These were large, tubular mechanisms which could accommodate a human body within them. A patient or recipient could thus be subjected to magnetic therapy through their entire body. These systems were large, cumbersome and relatively immobile. Examples of this type of therapeutic systems included U.S. Pat. Nos. 1,418,903; 4,095,588; 5,084,003; 5,160,591; and 5,437,600.
A second type of system was that of magnetic therapeutic applicator systems in the form of flexible panels, belts or collars, containing either electromagnets or permanent magnets. These applicator systems could be placed on or about portion of the recipient""s body to allow application of the magnetic therapy. Because of their close proximity to the recipients body, considerations limited the amount and time duration of application of magnetic therapy. Examples of this type system were U.S. Pat. Nos. 4,757,804; 5,084,003 and 5,344,384.
The third type of system was that of a cylindrical or toroidal magnetic field generator, often small and portable, into which a treatment recipient could place a limb to receive electromagnetic therapy. Because of size and other limitations, the magnetic field strength generated in this type system was usually relatively low. Also, the magnetic field was a time varying one. Electrical current applied to cause the magnetic field was time varying, whether in the form of simple alternating current waveforms or a waveform composed of a series of time-spaced pulses.
Briefly, the present invention provides a new and improved magnetic field generator for therapeutic applications. A magnetic field generator according to the present invention provides therapeutic application of a static magnetic field to a recipient. Magnetic field generators according to the present invention include a magnetic field generating coil in the form of a wound wire coil. A mounting member has the coil mounted on it. The mounting member also has an opening formed through it, the opening being of a size to permit insertion of a therapy recipient""s limb.
The magnetic field generator according to the present invention includes an electrical power supply which furnishes current to the magnetic field generating coil. Flow of current in the magnetic field generating coil causes a static electromagnetic field to occur within the opening of the mounting member for application to the recipient""s limb.
The magnetic field generator according to the present invention also includes a control circuit which regulates the amount of current flowing in the electromagnetic field generating coil. The control circuit permits adjustable regulation or control of the electromagnetic field strength generated by the field generating coil. The control circuit permits an operator to establish a desired field strength and then regulates the amount of power available to the field generating coil to achieve the established field strength.
The field generating coil of the present invention is of a size and capacity to generate substantial static electro-magnetic fields, such as up to a range of around 4000 gauss. A cooling system is provided with the magnetic field generator to remove heat during operation of the field generating coil.
The magnetic field generator is also provided with shielding externally of the field generating coil and the mounting member. The magnetic field generator is also enclosed in a housing which has an access passage for insertion of a recipient""s limb into the opening of the mounting member. The housing is mounted on a transport carriage which supports the magnetic field generator, while allowing ease of movement of the magnetic field generator from place to place.